May 1998

by Steve Stefanik

The only planet to come into play in the evening sky this month is the puny planet Pluto. With a miniscule magnitude of 13.7 it passes unnoticed to naked-eye observers among the stars of the constellation Ophiuchus. A telescope of 8 inches in diameter or more is needed with a camera and film or a blink comparator to confirm its planetary movement against the background stars from one night to the next. One positive note is that it will be at its brightest when it reaches opposition directly opposite us from the sun on the 28th if you want to try your luck.

With the planets out of the nightsky, May is a good time for deep-sky observing of galaxies. The constellations Leo (the lion), Virgo (the maiden), Coma Bernices (Bernices hair), Canes Venatici (the dogs), and Ursa Major (the Great Bear) are all high in the sky at nightfall. These constellations contain the greater majority of known galaxies. You will need a telescope of course, and the bigger the better! There is no other site like the myriad galaxies of the Virgo Cluster. Also nearby is the spectacular globular cluster M13, in the constellation Hercules.

Also rising in the east are the three bright stars which mke up the "Summer Triangle", Vega in the constellation Lyra the musical stringed instrument, Deneb in the constellation Cygnus the swan, and Altair in Aquilla the eagle.

The real attraction of the month is the parade of planets appearing in the east before sunrise. It begins by 3:00 a.m. when the twin planets of Uranus and Neptune rise in southeast among the dim stars of Capricorn followed by the bright -2.2 magnitude supergiant Jupiter around 4:00 a.m. Then the brilliant -4.1 magnitude planet Venus appears about an hour later. Venus is on its way down and Jupiter is rising. They continue to separate with each passing day as Jupiter rises earlier and earlier while Venus rises later and later until it disappears into the glare of the rising sun by the end of the month. The pair passed within half a degree of each other last month. They start off this month about 8 degrees apart but will be 37 degrees apart by the end of the month.

Saturn and Mercury join the procession by mid-month. They are within 0.8 of a degree of each other on the 12th and Venus passes Saturn within 0.3 of a degree on the morning of the 29th.